Processes for preparing alkali soluble aqueous polymer emulsions useful as thickeners are known in the art. Because such alkali soluble aqueous polymer emulsions useful as thickeners contain large amounts of carboxyl-functional monomer and also a monomer having surfactant characteristics, their production has proven to be difficult. In particular, during the polymerization process, some of the polymer plates out on the reactor walls and other reactor surfaces and grit particles form in the aqueous polymer emulsion product.
While some prior art processes have addressed this problem, see, for example, U.S. Pat. No. 4,801,671, such processes have not proven satisfactory from a commercial standpoint. It has long been desired to provide a process for producing alkali soluble aqueous polymer emulsions useful as thickeners in which plating and grit formation is minimized or eliminated during the process.